The present invention relates to sensing edges for automatic doors and, more particularly, to bilateral sensing edges which can be readily mounted on either side of the door.
Sensing edges for doors are generally well known. Such sensing edges generally include an elongate sheath in which a force sensing switch (sensor) is positioned. Upon the application of an undesired force to the sheath, the sensor actuates suitable control circuitry for controlling the movement of the door. The sensor, positioned within the sheath, typically comprises a pair of flexible, electrically conductive sheets positioned on the upper and lower sides of a layer of nonconducting foam having a plurality of openings extending therethrough from the upper to the lower side. Upon application of force to the sheath, either or both of the conductive sheets are deflected into electrically conductive engagement with each other through the openings in the layer of foam, to thereby actuate suitable control circuitry for controlling the door.
The typical sensing edge includes conductors attached to the sensor for transmitting the sensing signal to appropriate control circuitry mounted to one side or the other of the door external to the sensing edge. In a typical sensing edge, the conductors exit the sheath of the sensing edge through an aperture that is located either on the end surface of the sheath or on the top edge or side of the sheath.
It is very desirable for the conductors to exit from the inside of the sensor edge in order that the conductors be less susceptible to damage and to avoid interference with the door operation. However, a conventional sensing edge that employs an inside exit for the conductor requires the manufacture of both right hand and left hand versions of the sensing edge in order to properly place the conductors going to the control circuitry located on the inside of the door for both right and left handed door control circuitry installations. An additional problem may arise if an installer goes to the job site and, in the middle of an installation, discovers that for some reason the control circuitry must be located on a different side of the door than was originally planned. He must then leave the job site to exchange the sensing edge that is currently in his possession, for another sensing edge which has the conductors placed on the other side of the sensor edge.
The present invention is directed to a sensing edge for a door for sensing objects that come into contact with the sensing edge during door closing that is compatible with both right hand and left hand door control circuitry installations. The sensing edge in the present invention overcomes the problems inherent in the prior art by providing a means for routing the conductors to either the front side or the back side of the sensing edge after the sensing edge is completely fabricated. Thus a single model of the sensing edge can be used for both left handed and right handed door installations. The result is that only one item need be manufactured for both left and right handed door installations and the installer need only take a single sensing edge to the job site with the assurance that the job requirements can be satisfied even if the installation parameters change during the installation. The ability to route the conductors to either the front side or the back side of the sensing edge makes the sensing edge bilateral.